Istanbul is warmest in August, averaging 30° by day and 22° at night. The wettest month is January with 90 mm, and the year brings about 580 mm in total.
Month by month
| Month | High | Low | Rain | Sea | Daylight | Good for |
|---|---|---|---|---|---|---|
| January | 10° | 4° | 90 mm | 10° | 9.4 h | Cool |
| February | 11° | 4° | 59 mm | 9° | 10.4 h | Cool |
| March | 11° | 6° | 59 mm | 9° | 11.7 h | Cool |
| April | 16° | 9° | 51 mm | 12° | 13.1 h | Sightseeing |
| May | 21° | 14° | 40 mm | 16° | 14.3 h | Sightseeing |
| June | 26° | 19° | 36 mm | 22° | 14.9 h | Beach weather |
| July | 30° | 22° | 22 mm | 24° | 14.7 h | Beach weather |
| August | 30° | 22° | 16 mm | 25° | 13.6 h | Beach weather |
| September | 26° | 20° | 27 mm | 23° | 12.3 h | Beach weather |
| October | 21° | 15° | 37 mm | 20° | 10.9 h | Sightseeing |
| November | 16° | 10° | 78 mm | 16° | 9.7 h | Sightseeing |
| December | 13° | 6° | 65 mm | 12° | 9.1 h | Mild |
High and low are average daily maximum and minimum, rain is typical monthly total, sea is the average surface temperature, daylight is the hours between sunrise and sunset mid-month. Climate normals from NASA POWER and NOAA MUR — averages, not promises.
When to go
Beach weather: June, July, August and September — highs around 28°, nights no colder than 19°, and at most 36 mm of rain in a month. The sea sits at 22–25° then.
Walking the city: April, May, October and November — highs of 16–21° and no more than 78 mm of rain a month.